L’Esperimento CLAS12 a JLab
Responsabile Locale
M. Contalbrigo
L.Pappalardo
Attivita gruppo III
1
Towards the 12 GeV era
L.Pappalardo
Attivita gruppo III
2
Towards the 12 GeV era
CLAS12 detector





Lumi up to 𝟏𝟎𝟑𝟓 𝒄𝒎−𝟐 𝒔−𝟏
High polarized electron beams
H and D polarized target
Broad kinematic range
Very good PID
Physics program:
- Hadron spectroscopy
- Nuclear effects in hadronization
- Nucleon structure (TMDs, GPDs)
L.Pappalardo
Attivita gruppo III
3
Towards the 12 GeV era
L.Pappalardo
Attivita gruppo III
4
The non-collinear structure of the nucleon

FF
DF
momentum
helicity
Boer-Mulders
transversity
pretzelosity
Sivers
L.Pappalardo

P
q


p  xP

pT
• TMDs depend on 𝑥 and 𝑝𝑇
• Describe correlations between
𝑝𝑇 and quark or nucleon spin
(spin-orbit correlations)
worm-gears
Attivita gruppo III
5
The non-collinear structure of the nucleon
momentum
helicity
Boer-Mulders
transversity
pretzelosity
Sivers
L.Pappalardo
worm-gears
Attivita gruppo III

P
q


p  xP

pT
• TMDs depend on 𝑥 and 𝑝𝑇
• Describe correlations between
𝑝𝑇 and quark or nucleon spin
(spin-orbit correlations)
• Provide a 3-dim picture of the
nucleon in momentum space
(nucleon tomography)
6
Ferrara group involved in exp. proposals
PAC39 (June 2012)
L. Pappalardo
Attivita gruppo III
7
The CLAS12 RICH
L. Pappalardo
Attivita gruppo III
8
The CLAS12 RICH
Progetto Premiale CLASMED
L. Pappalardo
Attivita gruppo III
9
RICH: GEANT4 simulations
L. Pappalardo
Attivita gruppo III
10
Photon Detectors: MA-PMT
The only option to keep the schedule is the use
of multi-anode photomultipliers (we consider the
promising SiPM technology as the alternative)
✓
✓
✓
✓
✓
✓
Mature and reliable technology
Large Area (5x5 cm2)
High packing density (89 %)
64 6x6 mm2 pixels cost effective device
High sensitivity on visible towards UV light
Fast response
Torus fringe fields in the
RICH photo-detector area
L. Pappalardo
Attivita gruppo III
11
Front-End Electronics
PMTs
ADAPTER BOARD
FPGA board (Jlab)
ASIC BOARD
FPGA BOARD
ASICs board (Ferrara)
L. Pappalardo
Attivita gruppo III
12
RICH: optical characterization of aerogel
Transmission (cm)
TH (l ) = A × e
-
Ct
l4
=e
-
t
LA
×e
-
t
Ls
L A = -t / ln A
Absorp. length
L S = -l 4 / C
Scattering length
1
0.8
NOV105_CERN1
0.6
NOV105_CERN2
CHB105_BTR12
CHB105_PDR12
0.4
0.2
Cherenkov photon yield
H8500 QE
0
0.2
0.4
0.6
0.8
Wavelength (mm)
L. Pappalardo
Attivita gruppo III
13
Aerogel Chromatic Dispersion
Measured by prisma method:
Measured by prototype with optical filters:
𝛿
fit
MC
a0 l 2
n -1 = 2
l - l02
2
L. Pappalardo
Expected value from density:
n2(400nm) = 1+0.438r
n(400nm) = 1.0492
Attivita gruppo III
14
Proximity Focusing RICH Prototype
Clear hadron separation up to the CLAS12 maximum
momentum
H8500
p
p=8 GeV/c
p=6 GeV/c
1m gap
K (x40)
8
Radiator
GeV
beam
beam
P (x40)
Aerogel: n=1.05
2cm thickness
qC (mrad)
qC (mrad)
P
Ring Coverage ~ 80%
L. Pappalardo
Attivita gruppo III
c
q
n
(GeV/c)
(mrad)
(mrad)
6
306.5
1.41
6.9
7
306.8
1.40
4.7
8
307.6
1.40
3.9
15
Activity with SiPM
SiPM might offer a cheaper and more efficient solution,
expecially in a longer time perspective for other sectors
L. Pappalardo
Attivita gruppo III
16
SiPM Characterization
Current (mA)
Humidity and Temperature
sensors
Black box
N2 inlet
10
2
10
1
-1
10
Fast
Pre-amplifier
60 C
40 C
55 C
35 C
50 C
30 C
25 C
10
10
45 C
10 C
5C
-3
0C
-4
-5 C
10
-10 C
Peltier Cell
Derivative
-5
SiPM
10
10
Working
point
1
25
Air cooling
L. Pappalardo
15 C
20 C
-2
27.5
30
32.5
35
Vbias (V)
Break-down
Voltage
Attivita gruppo III
17
Npe
N. events
SiPM Characterization
4000
6
5
10
2
4
3000
3
2000
10
2
1000
1
0
0
0
1
2
3
4
1
-8
-6
log(Dt) (s)
N. events
Npe
-4
1250
1000
750
500
250
0
-8
-6
-4
log(Dt) (s)
L. Pappalardo
Attivita gruppo III
18
SiPM Prototype Results
Run 489
Y [mm]
150
3
10
N events
100
50
102
0
-50
10
TDC D t
-100
-150
-150
-100
-50
0
50
100
150
Time Res. [ps]
X [mm]
220
-25 °C
0 °C
+25 °C
210
200
190
180
170
160
150
140
130
120
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Overvoltage [V]
L. Pappalardo
Attivita gruppo III
19
1
RICH Landscape
✔
Project Premiale CLASMED
✔
HadronPhysics3: 3D-Mom
✔
DOE funded R&D for a future EIC: SiPM
✔ HPH: TMD-next and next-DIS (submitted)
Ferrara in 2015:
✔
RICH Project Coordination
✔
Front-End electronics prototyping and production
✔
Aerogel characterization and acceptance tests
✔
SiPM applications for RICH and Medical Imaging
GOAL: 1st sector ready by the end of 2016
L. Pappalardo
Attivita gruppo III
20
Il gruppo di Ferrara @ JLAB12
Responsabilita’:
• M. Contalbrigo: responsabile locale di Jlab12
• M. Contalbrigo responsabile progetto RICH
• M. Contalbrigo & L.P. Co-spokesperson di diverse proposte di
esperimento (PAC34,37,38,39)
Contributi principali:
• RICH detector (Contalbrigo, A. Movsysian, Luca Barion)
- Simulazioni GEANT4 e codice di ricostruzione
- Realizzazione prototipi e test su fascio (CERN, LNF)
- Caratterizzazione proprieta’ ottiche radiatore (@ SILAB)
- SIPM Applications on RICH and Medical Imaging
• Configurazione magnetica per HD_Ice target (M. Contalbrigo, M. Statera)
• Studi di fattibilita’ e proiezioni dei risultati per proposte di
esperimenti con CLAS12 (M. Contalbrigo, Luciano Pappalardo)
L. Pappalardo
Attivita gruppo III
21